r10916: - finished the 'operational' ldb module

r10916: - finished the 'operational' ldb module

- removed the timestamps module, replacing it with the operational module

- added a ldb_msg_copy_shallow() function which should be used when a module
  wants to add new elements to a message on add/modify. This is needed
  because the caller might be using a constant structure, or may want to
  re-use the structure again

- enabled the UTC time attribute syntaxes in the operational module
(This used to be commit 61e8b010223ac6a0573185008f3719ba29574688)